Title page for ETD etd-08112005-224301

Design and Testing of Off-The-Shelf Electronic Components for an Acoustic Emission Structural Health Monitoring System Using Piezoelectric Sensors

Degree

Master of Science

Department

Mechanical Engineering

Advisory Committee

Advisor Name

Title

Wicks, Alfred L.

Committee Chair

Johnson, Martin E.

Committee Member

Robertshaw, Harry H.

Committee Member

Keywords

acoustic emission

operational amplifier

charge amplifier

high pass filter

low pass filter

line driver

wave propagation

Date of Defense

2005-08-03

Availability

unrestricted

Abstract

The safety concern of aging aircraft is a rising issue in terms of both safety and cost. An aircraft structure failure during flight is unacceptable. A method needs to be developed and standardized to test the integrity of both commercial and military aircrafts. The current method to test the structure of an aircraft requires the aircraft to be taken out of service for inspection; this is costly due to the inspection required to be performed and the lost use from downtime.

A novice idea of an on-site structural health monitoring (SHM) system has been proposed to test the integrity of aircraft structure. An on-site system is a system that can be used to perform inspection on an aircraft simultaneously while the aircraft is in use. This SHM system uses the principles of active lamb wave and passive acoustic emission through the use of piezoelectric sensors as the sensing elements. Piezoelectric sensors can be used both as an input device and as a sensing element.

This research focuses on the development of the major data acquisition electronic components of the system. These components are charge amplifier, high pass filter, low pass filter and line driver. A charge amplifier converts a high impedance signal to a low impedance signal. A high pass filter attenuates the low frequency content of a signal, while a low pass filter attenuates the high frequency content of a signal. A line driver converts a low current signal to a high current signal. All of these components need to operate up to a frequency of 2 MHz. Off-the-shelf electronics will be used for prototyping as custom components will not be feasible at this point of the research.